In the substractive color photography having normally been used for obtaining color images in the field of photographic technology, it is popularly known that a dye image is formed in such a process that an aromatic primary amine type color developing agent (hereinafter called simply a color developing agent) is used so as to develop exposed silver halide grains and to react the resulted oxidation products of the color developing agent and, thereby, the dye image is formed.
In the above-mentioned process, cyan, magenta and yellow dye images are ordinarily formed by making use of a phenol or naphthol type cyan coupler, a 5-pyrazolone, pyrazolino-imidazole, pyrazolotriazole, indazole or cyanacetyl type magenta coupler and an acylacetamide or dibenzoylmethane type yellow coupler, respectively.
It is desired that the dye images obtained in the above-mentioned manner are not to be faded and discolored even if the dye images are exposed to light for a substantially long time or the dye images are preserved in the conditions of high temperature and humidity. It is, however, well known that the color fastness of such dye images against rays of light including ultraviolet or visible rays still do not reach a satisfactory level, but the dye images are readily be faded and discolored when a light-sensitive material having such a dye image is irradiated by the rays of light active to the light-sensitive material. With the purpose of eliminating the above-mentioned disadvantages, there have so far been some proposals in which a coupler relatively less in fadability and discolorability is selected out, an ultraviolet ray absorbing agent is used so as to protect a dye image from ultraviolet rays, an antifading agent is used so as to prevent a dye image from fading caused by light and so forth.
For example, in the proposed method of improving a dye image in color fastness against light by adding and compounding an ultraviolet ray absorbing agent into a color light-sensitive material, the color fastness of a dye image against light may remarkably be improved more than in the case of not adding any ultraviolet ray absorbing agent. On the other hand, when using such a quantity of the ultraviolet ray absorbing agent as is sufficient to display an excellent effect, there arises such a disadvantage that a dye image may not be avoided from staining because the ultraviolet ray absorbing agent itself is tinted. Besides, even if such an ultraviolet ray absorbing agent is used, no color fading prevention effect can be displayed on any dye image faded by visible rays of light. There has accordingly been a limit in the improvement effects of ultraviolet ray absorbing agents on color fastness against light.
On the other hand, the antifading agents for preventing a color fading caused by rays of light include, for example, such a bisphenol as those described in Japanese Patent Examined Publications Nos. 31256/1973 and 31625/1973; a pyrogallol, a gallic acid and the esters thereof, such as those described in U.S. Pat. No. 3,069,262; an .alpha.-tocophenol and the acyl derivatives thereof, such as those described in U.S. Pat. No. 2,360,290 and Japanese Patent Publication Open to Public Inspection (hereinafter called Japanese Patent O.P.I. Publication) No. 27333/1976; such a 6-hydroxychroman as those described in U.S. Pat. Nos. 3,432,300 and 3,574,627; such a 5-hydroxychroman derivative as those described in U.S. Pat. No. 3,573,050; such a 6,6'-dihydroxy-2,2'-bisspirochroman as those described in Japanese Patent Examined Publication No. 20977/1974; such an organic metal chelated compound as those described in U.S. Pat. No. 4,050,938 and Japanese Patent O.P.I. Publication Nos. 62826/1979, 62987/1979, 82385/1979 and 82386/1979; such a 6,6'-dihydroxy-2,2'-bisspirochroman dialkylether as those described in Japanese Patent Examined Publication No. 19765/1982; such a hydroquinone dialkylether as those described in Japanese Patent Examined Publication No. 24257/1981; such a compound having a sterically hindered phenol group as those described in Japanese Patent O.P.I. Publication Nos. 48535/1979 and 222853/1985; and such a polyalkyl piperidine type compound as those described in Japanese Patent Examined Publication No. 20617/1982, Japanese Patent O.P.I. Publication Nos. 114036/1983, 119351/1984 and 116747/1984; and so forth.
Among the above-mentioned dye image stabilizers, the particularly preferable stabilizers against light for yellow dye images include, for example, the compounds each containing the above-mentioned sterically hindered phenol group and polyalkylpiperidine type compounds. Namely, with the compounds each containing the sterically hindered type phenol group or the polyalkylpiperidine type compound may be able to increase the color fastness against light of dye images without any deterioration caused by a preservation in the dark and, further, any undesirable discoloration (i.e., any stain) caused by light, heat or moisture.
On the other hand, however, when such compounds each containing the sterically hindered phenol groups (hereinafter abbreviated to HP) or such polyalkylpiperidine type compounds (hereinafter abbreviated to PAP) are used in an amount capable of sufficiently increasing in color stability against light, it was found that there were the disadvantages that the color developability of couplers were lowered and the gradation or maximum density was also lowered. The above-mentioned disadvantages are seriously emphasized particularly when carrying out a rapid processing or removing benzyl alcohol from a color developer with the purpose of preventing environmental pollutions.
In the meantime, when the above-mentioned HP or PAP is so limited to add as not to lower the color developability of couplers used under the above-mentioned development conditions, the stabilizing effect of these compounds will seriously be reduced.